As the first days of spring bring warm weather and blossoming flowers to the Cambridge area once again, plant scientists at the Arnold Arboretum have a lot to celebrate.

The recent opening of the Weld Hill Research Building added 44,000 square feet of space in a center featuring state-of-the-art equipment and lab space for the scientists working with the Arboretum.

The building, which is located near the Arboretum in Boston at 1300 Center Street, was given its final approvals by the city of Boston in December, and  researchers have been in the process of moving to the new facility since January.

“The great thing about the expansion is that we’re actually bringing all of our research into one location. Previously, they were scattered throughout labs in Cambridge, not even in the same building, not being anywhere near the Arboretum,” said Faye M. Rosin, the laboratory administrator for the new facility. “This allows everyone to be in one place, where you can have interaction, you can just walk outside, go collect some materials, and just use them in your experiment.”

The Director of the Arnold Arboretum, William “Ned” Friedman, echoed this sentiment.

“It’s all about bringing the research mission, which has been here at the Arnold Arboretum for over a century, to the highest level of having the laboratory facilities right here on site,” said Friedman. “It allows us to invite the world in, invite Harvard undergraduates here.”

There are already many active research projects at the facility, according to Rosin, including studies in evolution of floral organs, relations between trees of the gymnosperm plants, and water relations in plants.

Friedman will be offering a freshman seminar in the Fall. The class will make use of the Weld Hill facility as it recreates some of Darwin’s experiments. The seminar will use of the laboratory equipment, although labs are only open to graduate research. According to Rosin, undergraduate teaching labs are under development and should be available in the near future.

The facility includes twelve greenhouses, plant growth chambers, laboratories, and administrative offices with room for 48 researchers and assistants, plus space for administrators and staff.

“What this really represents is a greater sort of integration of the Arnold Arboretum with the teaching and research positions that have always been a part of Harvard’s mission, now with a building to put it all in,” Friedman said.

The building was also designed to be environmentally friendly, according to the Arboretum’s website. Among other sustainable features, it incorporates a subterranean geothermal heat exchange system.

The Arboretum, part of Boston’s “Emerald Necklace” of parks, sits on 265 acres of land in the Jamaica Plain and Roslindale neighborhoods of Boston, and contains 15,052 separate species of plants, with emphasis on woody species of North America and eastern Asia, according to its website.

Although the park is privately managed by Harvard as its own department, the land is owned by the City of Boston and used by the University under a 1,000-year lease.